Hydrocarbon reclamation method and assembly

ABSTRACT

A method for removal of hydrocarbons from solid particulate matter provides a chemical treatment which moves particulate matter combined with a water and chemical mixture which is moved progressively through separation tanks to remove the particulate matter from the hydrocarbons after coating and allow the hydrocarbons to float free from the particulate substrate. The removal apparatus consists of a series of tanks through which the coated and fouled solid material is moved to progressively remove hydrocarbons from the surface of the solid material leaving the solids in one stream and the hydrocarbons in a second stream for disposal or further use.

FIELD OF INVENTION

The present invention relates to a method and apparatus for recovery of hydrocarbons found in mud, dirt, or tar sands; more specifically, for a method of mechanically and chemically treating hydrocarbon contaminated particles for recovery of the hydrocarbons and the environmentally acceptable disposal of the particulate matter utilizing a recirculating water stream.

BACKGROUND OF INVENTION

Disposal and recovery of hydrocarbons found in oils, pit bottoms, pit sludge, foul sand, dirt around plants, drill cuttings, naturally occurring tar sands or bitumen seams are problematic in the industry because of the potential for contamination of fresh water bodies, and the waste of hydrocarbons bound up with the sand or drill cuttings. “Substrate” will be used herein to describe the constituent particles carried, or which are coated by, the hydrocarbon; and, it is believed that all forms of hydrocarbon-coated substrates could be remediated using this method. Drill cutting cleaning methods and apparatus are well known in the trade. Other prior forms of remediation of these materials depend on heating or incineration, or use abundant quantities of water or other dangerous chemicals.

The present invention uses neither heat nor noxious chemicals, and recirculates the water used for remediation of the hydrocarbons from the substrate. The chemical additives of this method are generally well known. Those formulations found in U.S. Pat. No. 5,084,263 to McCoy et al. have been found to be useful, especially Solutions 1, 4, and 6, described in Cols. 7-9 of that patent which is adopted by reference herein. Other oil treating chemicals, such as commercially available emulsion-breakers and surfactants, can be adopted for use with this method.

SUMMARY OF INVENTION

The described method for separating hydrocarbon-fouled particulate matter or substrate comprises the steps of mixing the fouled substrate with water to form a slurry then placing the slurry in a contact tank to be fed through a vacuum eductor with a water and chemical mixture thus permitting a first separation of the hydrocarbons from the particulate matter. The slurry is allowed to settle in an oil separation tank. The remaining slurry output from the contact tank is mixed with additional water and moved to a first retention zone and cyclone system for additional separation of particulate matter from the slurry. From there, the output from the first retention zone and cyclone system can move to a mechanical shaker for separation of the solid particulate matter from the remaining water and return the water to a recirculating loop and collect hydrocarbons in an oil recovery tank by selective separation of the hydrocarbons from the particulate matter for removal. The hydrocarbon coating on the substrate is described as a “foulant” but can be economically valuable if removed from the substrate. Whether useful or subject to disposal the hydrocarbon foulant will be the material removed from the substrate by this process and the water and chemical mixture.

Specifically, a method for separating hydrocarbon-fouled particulate matter can comprise mixing the fouled particulate matter from a hopper by moving a water and chemical mixture through a vacuum-shearing eductor to form a slurry; placing the slurry in a contact tank to thoroughly coat the fouled particulate matter from the eductor to form a slurry of mixed water and chemical on a coated substrate; moving the slurry into a series of separation tanks permitting separation of the hydrocarbons from the particulate matter while allowing overflow of the separated hydrocarbon to the top of the each successive tank to a final collection tank and the particulate matter to be removed through a vacuum shearing eductor on the bottom of the each separation tank to an underflow line; selectively recycling the water and chemical mixture to the initial separation tank and the vacuum-shearing eductor on an inlet hopper from the final collection tank; and, collecting hydrocarbons in a recovery tank by skimming removal of the hydrocarbons from each separation tank in the series and moving the skimmed hydrocarbon to a hydrocarbon collection system. Additionally, the method can further comprise providing sufficient pressure to drive a water and chemical treatment mixture through a vacuum-shearing eductor on the series of separation tanks using one or more pumps; moving the hydrocarbon-fouled particulate matter to at least one shaker and cyclone separator, separating solids from the water and chemical mixture; and discarding the solids obtained from the at least one shaker and cyclone separator and returning the water and chemical mixture to the initial vacuum shearing eductor for mixing with the hydrocarbon fouled particulates in the hopper.

This method for separating hydrocarbon-fouled particulate can also move the remaining slurry output from the shaker through a desander/desilter system into at least one additional shaker for further removal of particulate matter to provide a further separation of water from the particulate matter; and, discard the solids obtained from the desander/desilter system and shaker and return the water and chemical mixture to the initial vacuum-shearing eductor for mixing with the hydrocarbon fouled particulates in the hopper.

The closed-loop hydrocarbon reclamation system is fashioned by combining a collection hopper for the deposit of a hydrocarbon-contaminated substrate in a slurry; a vacuum-shearing eductor to coat each particle of the substrate with the water and chemical to facilitate separation of hydrocarbons from hydrocarbon-contaminated substrate; a hydro-cyclone retention tank connected to the vacuum-shearing eductor for complete mixing of the water and chemical mixture and hydrocarbon-contaminated substrate; a plurality of settling tanks connected to the hydro-cyclone for removal of hydrocarbon-contaminated substrate from the water and chemical mixture taken from the bottom of each settling tank through a vacuum-shearing eductor, permitting the hydrocarbons floating on the top of each successive settling tank to flow into a final collection tank and allowing the water and chemical mixture to be re-circulated to continue the process and the cleaned substrate to be discarded. Returned water is processed through an ionizer to facilitate breaking of an emulsion of hydrocarbon and water by electrochemical means. The ionizer is connected to a first settlement tank to ionize water flowing through the settlement tank. The hydrocarbon reclamation system permits each vacuum-shearing eductor on any separation tank to be independently controlled by a centralized control system to facilitate control of the movement of separated water from the hydrocarbon overflow from each separation tank. The output of any vacuum-shearing eductor on any separation tank can also move from each eductor to an accumulator which allows the output to flow into a scalping shale shaker allowing removal of particulate matter from the water and chemical transporting the particulate matter, then flow into a desander/desilter on a second shale shaker permitting the water to be returned to the first settlement tank and the remaining particulate matter to be removed from the water and chemical stream.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic process flow diagram of the apparatus to recover hydrocarbons from particulate materials and water.

FIG. 2 is top plan view of the entire apparatus used for performing this method.

FIG. 3 is a perspective view of the entire apparatus for accomplishing this method.

FIG. 4 is a schematic process flow diagram of an alternative apparatus without the particulate handling devices of the apparatus shown in FIG. 1.

DETAILED DESCRIPTION OF SEVERAL EMBODIMENTS OF THE APPARATUS AND METHOD FOR UTILIZING THE METHOD

As shown in FIG. 1, this closed loop system uses water to wash and strip hydrocarbons from sand or particulate matter through a combined weir and shaker system, assisted by a chemical bath to break the adhesion of the hydrocarbons to the particles. Input stream 10 provides the tar sands, bitumen, or contaminated soils or clay into a macerator 31 driven by motor 32 to break the larger pieces of material into a smaller grained material in hopper 30. This system is fabricated with an inlet tank 30 where hydrocarbon substrate is introduced to the system, accomplished by a front-end loader, augur delivery systems or any other method of moving the hydrocarbon-coated substrate into the inlet tank 30. Water and chemical mixture, which is provided from water source 185 and chemical tank 80, is circulated through the primed system to hopper 30 for the initial wetting of the slurry.

The wetted slurry is moved out of hopper 30 from a flow of water and chemical through shearing eductor 40 into line 50 and thereafter to hydro-cyclone 60 for continued wetting and mixing. The hydro-cyclone 60 serves as an agitation retention tank rather than for separating or categorizing the outflow from the feed hopper 30. This could be a mixer or agitated tank without departing from the spirit or intent of this disclosure.

The slurry, after leaving the hydro-cyclone 60, is moved through line 70 to the first separation/separation tank 110. The amount of chemical loaded into the system from tank 80 through line 90 is controlled by automatic valve 100 which uses signals from a programmable logic control or centralized control system (PLC) to maintain the proper level of saturation within the system.

The first separation/settlement tank 110 allows the first separation of hydrocarbons from the particulate material which settle to the bottom where it is moved through the second shearing eductor 114 through line 118 to accumulator box 160′. From the accumulator box 160′ the water and chemical soaked particulate material moves to the scalping shaker screen 160 where the particulate matter that separates is moved through line 164 to the disposal line for solids 174. If the automatic sensors detect excessive hydrocarbon coating of the particulate matter moving through the discharge line 174, a second chemical tank 155 can be activated to coat the material prior to disposal. Solids sent from each of the shale shakers 160, 170 to the solids collection facility where they can be either disposed safely or, if useable as aggregate, to be recycled. This final chemical treatment can be made of the cuttings removed to assure complete removal of residual hydrocarbons on the particulate substrate removed through the shale shaker output from this second chemical tank 155, prior to disposal or recycling.

The finer particles, along with the water/chemical solution, are captured and moved through line 168 to a desanding/desilter combination 171 where, after removal of material, they are moved into the second shale shaker 170. The finer particulate material is removed from the second shale shaker 170 through line 174 to be discarded in the particulate dump and the resulting water/chemical solution with the remaining contamination is moved back into the first separation tank 110 where the process continues. Separated hydrocarbons which are less dense than the water float on the top of the first separation/settlement tank 110 and are moved from the first separation/settlement tank 110 to the second separation/settlement tank through an overflow skim line 119. In a similar fashion, the heavier and more dense particulate material with the water/chemical solution moves to the bottom of the second separation tank 120 where it is removed through the third shearing eductor 124 and moved through line 128 to accumulator box 160′ then through line 159 to the scalping shaker 160 where the process described above is repeated. The lighter hydrocarbon overflow from the second settlement tank 120 moves through overflow line 129 to third settlement tank 130, where as previously described, the settled portion of water/chemical solution and particulate are removed from the tank 130 with shearing eductor 134 and then through line 138 to accumulator box 160′ where the shaker process is repeated.

The quiescent overflow from the third tank of hydrocarbons moves through line 139 to the final tank 140 where the top is removed through line 150 to the hydrocarbon collection system 150 which could be a pipe system or storage battery depending on the amount of hydrocarbons recovered from this process. The heavier water/chemical solution is returned to the closed loop system through line 184 where it is combined with as much fresh water from line 185 as needed to continually move the particulate material through the system through control valve 187. Motive force is provided by pump 186, which, in this embodiment, is a 40 HP motor moving the solution through line 188 to the settlement tanks and the original hopper 30. The initial shearing eductor moving the most contaminated materials is provided a flow through pump 200 which in this embodiment is a 100 HP pump. This system also provides an ionizer 99 on the water/chemical feed line into first settlement tank 110. The ionized water facilitates the breaking of the emulsified oil/water mixture found in the re-circulated water/chemical mixture as a function of the zeta ( )potential from the ionizer 99.

FIG. 2 is a top view of the system described above. Inlet tank or hopper 30 is filled with the substrate having a coating of hydrocarbons as previously described. The macerator is not shown in this view. Hydro-cyclone 60 is situated between the outflow of the hopper 30 and the first settlement tank 110. Inlet tank 30 feeds to a hydro-cyclone 60 which both continues the agitation and coating of the hydrocarbon-covered substrate with the water/chemical mixture before moving into the first separation/settlement tank 110 where the initial separation occurs. Separated water and particulate matter are moved into the accumulator box 160′ through line 118 and then into the scalping shale shaker 160, where the initial separation of particulate from the slurry of mixed particulate and water/chemical mixture occurs. The remaining slurry is then moved into the desander/desilter 171 combination atop the second shale shaker 170 allowing the water to be returned through line 162 to the first precipitation/settlement tank 110. The separation of the hydrocarbon begun in the first separation/settlement tank 110 also continues in the second tank 120 where it is allowed to further separate from the water/chemical mixture. Settlement particulate matter is moved from tank 120 through line 128 into accumulator box 160′ where it drops into the scalping shaker 160 and thereafter to the desander/desilter 171 and the second shale shaker 170 permitting separated water to be returned through line 162 to the first precipitation/settlement tank 110. The same separation/settlement processing of the increasingly refined water occurs in the third tank 130 where the wetted particulate matter is moved through line 138 in a similar manner into the accumulator box 160′ thence to scalping shaker 160 and then desander/desilter 171 and the second shale shaker 170 and back to the initial tank 110 to continue the process. As water floats over from tank 110 to 120 and from tank 130 through overflow lines 139 to tank 140, it is increasingly clarified and the particulate matter sinking to the bottom of the tanks to be removed through lines 118, 128, and 138 to the shaker system is increasingly finer. The water and chemical treatment is pumped through a vacuum-shearing eductor 40 where it is mixed with the gravity-fed coated substrate and sheared as it moves through the vacuum-shearing eductor 40, and then into a separation/settlement tank 110. The precipitated particles of the substrate remaining in the water flow move in flow line 118 to the accumulator box 160′ and first shale shaker 160 (not shown in this view), and then into the desander/desilter combination 171 atop the second shale shaker 170 allowing the water to be returned to precipitation/settlement tank 110. Water continues to flow over from the top of each tank through tanks 110 to 120 then to 130 and finally into catch tank 140 where the precipitated particles of the substrate remaining in the water are removed through flow lines 118, 128, 138 to accumulator 160′. At each step of the flowing over the water is clarified as more and more particulate matter settles out of the water. This progressive coating, settling, and separation steps may be repeated serially through any number of individual separation tanks and shale shakers without departing from the spirit of this disclosure which is only limited by the space required for its installation. At least three separation tanks and at least two shale shakers are considered optimal. The final flow path from tank 130 flows through the overflow lines 139 into the final catch tank 140. Pump 186 moves the remaining clarified water back into the process loop to continue the flushing process started in tank 110.

As shown in the front perspective details of FIG. 3, the system commences with the loading of the substrate from a process stream through macerator (not shown in this view for clarity purposes) into a feed hopper 30 which mixes the substrate with the chemical and water stream clarified by cycling through the system from line in vacuum-shearing educator 40. Water and treatment chemical from a water source tank move into the primed system before admission of substantial quantities of slurry in hopper 30 with the hydrocarbon particles coating the sand. The mixed substrate and water mixture is moved through a line to a hydro-cyclone (not visible in this view) where it continues to thoroughly coat the slurry with the chemical introduced in the primed system from the water source tank and is fed to the first separation/settlement tank 110. Water circulates through this closed loop system from the final settlement tank 140 with pump 186 and is supplemented with additional water through a flow line which returns through the water return line through an ionizer, all as previously described. The fully mixed or coated hydrocarbon and substrate is sheared in the vacuum-shearing eductor 40 then moved into the hydro-cyclone into the first separation/settlement tank 110. A variable flow automatic valve system permits the water/chemical mixture to be moved through a second shearing vacuum educator which again mixes the settled portion of the first separation/settlement tank 110 with additional fluid which is moved into the accumulator box 160′ through line 118, then to a scalping shaker 160. The mixture of particulates and water/chemical treatment is moved into the scalping shale shaker and again agitated to allow heavier particulate matter to be separated out and moved into the disposal line. In this view the scalping shaker is obscured from view by accumulator box 160′, but the desander/desilter 171, common in the fluids-handling art, are readily identifiable on the second shaker 170 from which the solids are removed for disposal and the water/chemical solution coating the remaining finer solids are returned to the collection of separation tanks commencing with first separation tank 110 for recycling and further separation.

As shown in FIG. 4, an alternative embodiment of the described hydrocarbon recovery system can also be fabricated from a similar arrangement of a plurality of settling tanks 110, 120, 130, and 140, into which a series of flows of hydrocarbon-fouled particulate matter or substrate 10 is allowed to progressively separate from the water and chemical carrier. As shown in the process diagram of FIG. 4, the overall similarity of this arrangement removes the particulate handling or removing devices shown in FIGS. 1-3 as generally macerator on the initial hopper 30, accumulator box 160′, shaker 160, and the desanding/desilting filter system and shaker combination 170, 171, but retains the vacuum-shearing eductors 40 on the initial hopper, the hydro-cyclone 60, before moving the slurry into the first settling tank 110. A PLC system controls the rate of flow both into and out of each of the settling tanks 110, 120, 130 allowing them to remove the particulate matter from the bottom and allowing the separated hydrocarbon to rise to the top and flow from each tank in turn until collected in the final settlement tank. Water is recycled from the final settlement tank 140 to drive the shearing eductors 114, 124, and 134 on the separation tanks while the separated oil is skimmed from the top of the final settlement tank 140. Particulate matter or cuttings are removed from the system by selectively diverting water from the bottom of the final settlement tank 140 through the shearing eductors on the settlement tanks to move particulates to the underflow line 118 filled with the particulate matter coming off each settling tank 110, 120, and 130.

Additional water needed to keep the recirculation of the system is provided through inlet 485 into first settlement tank 110. Water separated in each settlement tank is recycled through the initial vacuum-shearing eductor 40 from pump 200 on return line 490 for moving the hydrocarbon-fouled slurry from hopper 30 into the hydro-cyclone 60 for complete mixing, thence through line 70 into the first settlement tank 110. Treating chemicals for breaking the oil/water emulsion can be added from treating chemical injection system 480 as needed to maintain separation of the constituent parts of the slurry. Ionizer 499 provides an ionized electrochemical charge to the emulsion flowing into the first settlement tank to assist in separation of the water and hydrocarbon emulsion. Separated oil commences rising to the top of each settlement tank and moves progressively through lines 119, 129, and 139 to the final separation tank where it is finally skimmed off and contained within a recovered oil collection system 150. This could be either a tank system, or pipeline for moving the collected oil for further processing. 

What is claimed is:
 1. A method for separating hydrocarbon-fouled particulate matter comprising: mixing the fouled particulate matter from a hopper by moving a water and chemical mixture through a vacuum-shearing eductor to form a slurry; placing the slurry in a contact tank to thoroughly coat the fouled particulate matter from the eductor to form a slurry of mixed water and chemical on a coated substrate; moving the slurry into a series of separation tanks permitting separation of the hydrocarbons from the particulate matter while allowing overflow of the separated hydrocarbon to the top of the each successive tank to a final collection tank and the particulate matter to be removed through a vacuum shearing eductor on the bottom of the each separation tank to an underflow line; selectively recycling the water and chemical mixture to the initial separation tank and the vacuum-shearing eductor on an inlet hopper from the final collection tank; and, collecting hydrocarbons in a recovery tank by skimming removal of the hydrocarbons from each separation tank in the series and moving the skimmed hydrocarbon to a hydrocarbon collection system.
 2. The method for separation of hydrocarbon-fouled particulate of claim 1 further comprising providing sufficient pressure to drive a water and chemical treatment mixture through a vacuum-shearing eductor on the series of separation tanks using one or more pumps.
 3. The method for separating hydrocarbon-fouled particulate of claim 1 further comprising: moving the hydrocarbon-fouled particulate matter to at least one shaker and cyclone separator, separating solids from the water and chemical mixture; discarding the solids obtained from the at least one shaker and cyclone separator and returning the water and chemical mixture to the initial vacuum shearing eductor for mixing with the hydrocarbon fouled particulates in the hopper.
 4. The method for separating hydrocarbon-fouled particulate of claim 3 further comprising: moving the remaining slurry output from the shaker through a desander/desilter system into at least one additional shaker for further removal of particulate matter to provide a further separation of water from the particulate matter; and, discarding the solids obtained from the desander/desilter system and shaker and returning the water and chemical mixture to the initial vacuum shearing eductor for mixing with the hydrocarbon fouled particulates in the hopper.
 5. The method of claim 1 wherein the hydrocarbon-fouled particulate matter is drill cuttings.
 6. The method of claim 1 wherein the hydrocarbon-fouled particulate matter is tar sands.
 7. The method of claim 1 wherein the hydrocarbon-fouled particulate matter is selected from one or more of the following materials: pit bottoms, pit sludge, foul sand, dirt around plants, or bitumen seams
 8. A closed-loop hydrocarbon reclamation system comprising: a collection hopper for the deposit of a hydrocarbon-contaminated substrate in a slurry; a vacuum-shearing eductor to coat each particle of the substrate with the water and chemical to facilitate separation of hydrocarbons from hydrocarbon-contaminated substrate; a hydro-cyclone retention tank connected to the vacuum-shearing eductor for complete mixing of the water and chemical mixture and hydrocarbon-contaminated substrate; a plurality of settling tanks connected to the hydro-cyclone for removal of hydrocarbon-contaminated substrate from the water and chemical mixture taken from the bottom of each settling tank through a vacuum-shearing eductor, permitting the hydrocarbons floating on the top of each successive settling tank to flow into a final collection tank and allowing the water and chemical mixture to be re-circulated to continue the process and the cleaned substrate to be discarded.
 9. The hydrocarbon reclamation system of claim 6 wherein the returned water is processed through an ionizer to facilitate breaking of an emulsion of hydrocarbon and water by electrochemical means.
 10. The hydrocarbon reclamation system of claim 7 wherein the ionizer is connected to a first settlement tank to ionize water flowing through said settlement tank.
 11. The hydrocarbon reclamation system of claim 6 where each vacuum-shearing eductor on any separation tank is independently controlled by a centralized control system to facilitate control of the movement of separated water from the hydrocarbon overflow from each separation tank.
 12. The hydrocarbon reclamation process of claim 6 wherein the output of any vacuum-shearing eductor on any separation tank moves from each eductor to an accumulator which allows the output to flow into a scalping shale shaker allowing removal of particulate matter from the water and chemical transporting the particulate matter, then flowing into a desander/desilter on a second shale shaker permitting the water to be returned to the first settlement tank and the remaining particulate matter to be removed from the water and chemical stream. 